OLED Display Subpixel Architecture for Efficiency
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Solution Overview
Problem
Existing organic light-emitting diode (OLED) displays face challenges in optimizing display performance, including low pixel pitch and poor light-emitting efficiency due to small pixel apertures and inefficient color filter usage.
Innovation Solution
The implementation of a four-subpixel design with a blue subpixel using a separate emissive layer and red and green subpixels sharing a common emissive layer, along with tandem diode configurations and optical cavity structures tuned for different colors, enhances light-emitting efficiency and color purity by optimizing emissive layer usage and cavity resonances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional OLED display structures are used, then manufacturing is simpler, but pixel pitch is low and light-emitting efficiency is poor
Solution Approach 1:
The display is divided into multiple subpixels (red, green, blue, yellow) within each pixel, with shared emissive layers between certain subpixels. This segmentation allows independent optimization of each subpixel's light-emitting characteristics while improving overall efficiency
Solution Approach 2:
The red and green subpixels share a common emissive layer, and the yellow subpixel shares another common emissive layer. This merging reduces the total number of emissive layers needed, increasing the aperture area and light-emitting efficiency without compromising color performance
2Productivity
If pixel aperture is increased to improve light-emitting efficiency, then light output improves, but pixel pitch decreases
Solution Approach 1:
The patent transitions from a conventional three-subpixel design to a four-subpixel design with shared emissive layers. This dimensional reorganization in the pixel structure allows larger aperture area while maintaining or improving pixel pitch through more efficient space utilization
3Measurement precision
If color filter elements are used in all subpixels, then color accuracy improves, but light-emitting efficiency deteriorates
Solution Approach 1:
The patent extracts and removes color filter elements from the blue subpixel, relying instead on the intrinsic blue emission from the emissive layer. This extraction eliminates the light loss associated with color filters while maintaining color accuracy through selective emissive layer design
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves light-emitting efficiency and color accuracy, allowing for higher effective resolution and better ambient light suppression, thereby enhancing the overall display performance of OLED devices.
Implementation Method 1
A display pixel may be provided with optical cavity structures. Cavity modification layers formed of transparent material of different thicknesses may be used to tune the wavelength resonances of cavities for subpixels of different colors.
Implementation Method 2
A pixel definition layer may be formed form a light-absorbing material to suppress ambient light reflections.
Implementation Method 3
An electronic device may include a display having an array of organic light-emitting diode display pixels... A blue subpixel may be formed using a first part of an emissive layer and red and green subpixels may share a second part of the emissive layer.
Data Source
AI summary
An electronic device may include a display having an array of organic light-emitting diode display pixels. Color filter elements may be used to allow the display to present color images. A blue subpixel may be formed using part of an emissive layer and red and green subpixels may share a separate second part of the emissive layer. In four-subpixel designs, a white or yellow subpixel may also share the emissive layer with the red and green subpixels. Tandem diode configurations may be used in which a blue subpixel has two blue diodes connected in series and other subpixels are formed from respective pairs of series-connected diodes. A pixel definition layer may be formed from a light-absorbing material to suppress ambient light reflections.